Syrian troops and tanks stormed into a southern city Monday in a sharp escalation of a bloody crackdown on anti-government protesters as the U.S. announced that it is considering imposing sanctions against President Bashar Assad's regime.
An eyewitness told The Associated Press that at least 11 people were killed when Syrian security forces entered the town of Daraa, a city of about 300,000 people near the Jordanian border where the monthlong uprising began. Large numbers of troops reportedly arrived in busloads before dawn and tanks moved in later as electricity, water and mobile phone service was cut.
"They have snipers firing on everybody who is moving," said a witness who spoke to the AP by telephone, asking that his name not be used out of fear for his own safety. "They aren't discriminating. There are snipers on the mosque. They are firing at everybody."
Syria has banned nearly all foreign media and restricted access to trouble spots since the uprising began, making it nearly impossible to get independent assessments.
Hours after troops entered Daraa, Syria sealed off its border with Jordan, according to Jordanian government spokesman Taher Edwan. But the head of Syria's customs department denied that the country had closed its land borders.
NPR's Deborah Amos reported from Lebanon that social media sites were quoting witnesses who said that Syrian security forces were firing into homes and that there were bodies on the streets. Activists also posted footage of what they said were troops firing throughout Daraa on Monday.
Amos also said seven government officials from the Daraa area had taken the unusual step of announcing their resignations on a satellite television channel in protest over the violence. Also Monday, a group of 100 prominent Syrians from across religious and sectarian lines wrote a public letter condemning the violence.
"We reached a turning point today and the only way to reach our target is to continue to demonstrate ... [peacefully] in the street," Mohammed Ali Atassi, a Syrian journalist and filmmaker, who was among the signatories. "And we are showing the rest of the world that we want our liberty and we are ready to fight to get it."
More than 300 people have been killed across the country since the uprising began, sparked by the arrest and alleged torture of teenagers for scrawling anti-government graffiti on a wall.
The relentless crackdowns on unarmed demonstrators in recent weeks have only served to embolden protesters, who started with calls for modest reforms but are increasingly demanding Assad's downfall.
"The anti-government movement has shown a remarkable resilience," Amos said. "These people are facing what they know is live fire. People die in these protests."
"We need international intervention. We need countries to help us," one witness in Daraa told the AP by telephone.
Amos said even the protest organizers acknowledge that the demonstrations have not reached critical mass.
"There are not protests in Damascus, the capital, and not in Aleppo, the second largest city," she said.
The State Department on Monday urged Americans to defer all travel to Syria, advised those already in the country to depart while commercial transportation is available and to limit nonessential travel within the country. Nonessential U.S. embassy staff and the families of all embassy personnel have been ordered to leave Syria. It said the embassy would remain open for limited services.
The Obama administration also said that it is pursuing "a range of possible policy options" against Syria. National Security Council spokesman Tommy Vietor said those options could include targeted sanctions against Assad's government.
White House rhetoric against Syria has ratcheted up in parallel with the violence, calling the government crackdown "completely deplorable" and condemning the bloodshed in the "strongest possible terms."
In Geneva, the U.N. human rights chief, Navi Pillay, said Syria has turned its back on international calls to "stop killing its own people."
"Instead, the government's response has been erratic, with paper reforms followed by violent crackdowns on protesters. ... The killings must stop immediately," Pillay said.
Still, the regime is clearly stepping up its efforts to crush the uprising, which has posed the gravest challenge to the 40-year ruling dynasty by Assad and his father, Hafez, before him. Although the army has been used before to quell demonstrations in recent weeks, its presence Monday was widespread and its tactics were heavy-handed.
But it was not entirely unexpected. There had been signs that the regime was planning to launch a massive push against the opposition.
Last week, Assad fulfilled a key demand of the protest movement by abolishing nearly 50-year-old emergency laws that had given the regime a free hand to arrest people without cause. But he coupled the concession with a stern warning that protesters would no longer have an excuse to hold mass protests.
When protesters defied his order and held demonstrations Friday they were met with a gunfire, tear gas and stun guns. Authorities then conducted sweeping arrests of activists and protesters.
Also Monday, witnesses said Syrian security forces had opened fire in the coastal town of Jableh, where police and army units fired from rooftops over the weekend even though there were no apparent threats and no protests in progress.
On Monday, witnesses said security forces in camouflage uniforms — some with their faces covered — and masked gunmen dressed in black were roaming the town's streets.
"Jableh is surrounded by security forces," the witness said, speaking to the AP by telephone. "The dead are in the mosques and the houses. We can't get them out."
Violence also was reported in Douma, a suburb of Damascus, where authorities were making sweeping arrests.
"The security has been heavy here since Friday, but overnight they cut off parts of the city from each other," another witness said.
With reporting from NPR's Deborah Amos in Beirut, Lebanon, and Scott Horsley in Washington, D.C. Material from The Associated Press was used in this story.